The present invention relates to a fastening system comprising a self energizing fastening element or fastener and a tool for initiating energization of the fastening element. The tool also provides means for assuring the fastening element is driven or inserted a controlled amount to a predetermined depth.
More particularly, the present invention relates to improvements in propellant actuated tools of the type described and claimed in U.S. Pat. No. 3,797,721 granted on Mar. 19, 1974. As is now well known and as described in the aforesaid patent, propellant actuated tools function to drive a fastener or fastening element into a work piece by the expanding gases produced by an associated propellant charge which is ignited by impact of an actuating member against the charge.
The inventive system includes a self energizing fastener which is utilized in connection with a tool to activate the self energizing fastener. The tool includes a barrel having a bore or fastener holding chamber terminating in an open end. The bore is shaped to receive and position the fastener. The fastener has a percussion activatable propellant charge which is energized by the impact received from an activating member positioned in the bore. The bore is formed to be of a length that is such that a portion of the fastener extends outwardly of the bore beyond the end of the barrel. More specifically, in operation the tip end of the fastener extends outwardly from the tool; and, striking the tip end of the fastener against the work surface into which it is to be driven, enables the activating member to initiate the energization of the propellant to drive the fastener into the desired work surface.
The present inventive system also provides a tool and fastener system that is efficient, reliable, safe, and troublefree.